1. Field of the Invention
The invention relates to a discharge lamp for the disactivation of micro-organisms having an emitted radiation suitable for disactivation.
2. Prior Art
There are known discharge lamps being used for disactivation of micro-organisms in gases and fluids. In German specification No. 1 679 567 a room air purifying device is described that cleans the air by the effect of ultraviolet rays. As a source of ultraviolet rays one preferably used is a low pressure mercury burner. An electric room air deodorizing device with ultraviolet low pressure burners is disclosed in German disclosure 1 492 460.
Also, a room disinfecting device is disclosed in German registered design 7 314 612 using quartz lamps emitting an ultraviolet radiation for the formation of ozone, the wave length range of which not beng exactly given.
A device for the disinfection of water by means of immersion lamps in which a discharge lamp is being arranged, is shown in U.S. Pat. No. 3,566,105 . The discharge lamp described therein concerns likewise a mercury discharge lamp.
Although the mercury discharge lamps described in the above mentioned arrangements are emitting radiations in the wave length range between 260 to 280 nm, corresponding to the wave length range for the optimum disactivation of micro-organisms, these discharge lamps present a series of disadvantages.
When using low pressure mercury burners, the disinfection arrangements occupy a rather large volume. The reason for this can be found in the small output of emitted radiation per centimeter of discharge length. In addition thereto the emitting maximum is at 254 nm, there is the further disadvantage that the effect of this radiation corresponds only to about 80% of that one in the wave length range of 260 to 280 nm.
Low pressure discharge lamps are susceptible to variations in temperature, as they are caused, for example, by air flowing past the discharge vessels, manifesting itself by a reduced emitting capacity.
Space-saving arrangements can be made by using high pressure mercury burners which, moreover, are less susceptible to variations of temperature. These, however, are subject to the disadvantage that only a small radiation portion is emitted in the wave length range of 260 to 280 nm, yet there appears radiation in the range of 400 to 450 nm causing a re-activation of the micro-organisms.